Jack Valenti is 82, and he still runs the Motion Picture Association of America with consummate skill, just as he’s done for 37 years now. “What’s remarkable is he’s managed to hold all the companies together even though we’re often fractious among each other and competitive and have heavily divergent issues — some of us have networks, some have cable companies, some have theme parks, some have the Internet. We’re all often truly impossible to deal with. Jack has held us together.”